1. Field of Invention
The present invention relates to a heat dissipation device, and more particularly to a heat dissipation device applicable to a portable electronic device.
2. Related Art
Currently, with the rapid development of electronic technology, consumers pay more attention to light, thin, and portable consumer electronic products. Thus, electronic products, like portable electronic devices such as notebooks, ultra mobile personal computers (UMPCs), and Personal Digital Assistant (PDAs), are all developed toward microminiaturization. For users who often travel outside, portable electronic products are easier to carry, thus greatly improving convenience in use.
The UMPC, for example, employs electronic elements with fast operating speed and extremely small volume. Consequently, the heat generation amount per unit area is increased. If the heat cannot be dissipated instantly, the over-high temperature may seriously affect the stability and efficiency of the electronic elements in operation, and may even reduce the service life of the computer or cause damages thereto.
To solve the heat dissipation problem of a portable computer, conventionally a fan is installed inside the computer for dissipating the heat generated by the electronic elements, and meanwhile lowering the ambient temperature in the computer. However, as the portable computer is short and thin, excluding the space occupied by the necessary circuit layouts and the electronic elements, the remnant free space inside the computer is limited, and it is difficult to add an extra heatsink fan.
In consideration of the overall heat dissipation efficiency of a computer, it is better to utilize a large fan for dissipating heat. In this manner, the circuit layout inside the computer must be changed to cater for the fan, which results in a high manufacturing cost and the increase of the volume of the computer due to the installation of the fan, which goes against the current consumers' requirements on light, thin, short, and small electronic products. In consideration of the circuit layout inside the computer and the volume of the computer, a micro fan is selected. However, the heat dissipation efficiency of the micro fan may hardly meet the heat dissipation requirement of micro electronic elements that generate large amount of heat.
The air introduced during the operation of the conventional fan may cause friction with members like the case and the air duct, and make noises of a certain frequency. As a fan is installed in a light and thin UMPC, the noises generated by the fan are directly transmitted to the outside without blocking, thus resulting in a severe noise problem. The technicians in the relevant art are in urgent need of finding a solution to eliminate the noise problem.